Social influence under uncertainty: decision-making in anonymous crowds

Abstract

Uncertainty and limited access to information may trigger unpredictable group dynamics and unsafe movements in urban crowds. Although such situations are common in everyday life, the socio-psychological mechanisms that guide decision making in crowds have scarcely been explored, apart from the controversially discussed concept of contagion. This experimental study aims to make an initial empirical approximation of this issue by examining how (non-)communication and group size affect the duration and homogeneity of group-level decisions in an anonymous setting. The results show that communication does not affect the duration of finding final solutions, but it can lead to both polarized or homogeneous outcomes. The absence of communication, on the other hand, may activate self-presentational concerns and lowers the possibility of highly homogeneous outcomes. These findings are discussed in light of mechanisms of social influence and conformity that could be identified through the videographic analysis of the experiments.